Truly stateless, optimal dynamic partial order reduction

Abstract

Dynamic partial order reduction (DPOR) verifies concurrent programs by exploring all their interleavings up to some equivalence relation, such as the Mazurkiewicz trace equivalence. Doing so involves a complex trade-off between space and time. Existing DPOR algorithms are either exploration-optimal (i.e., explore exactly only interleaving per equivalence class) but may use exponential memory in the size of the program, or maintain polynomial memory consumption but potentially explore exponentially many redundant interleavings. In this paper, we show that it is possible to have the best of both worlds: exploring exactly one interleaving per equivalence class with linear memory consumption. Our algorithm, TruSt, formalized in Coq, is applicable not only to sequential consistency, but also to any weak memory model that satisfies a few basic assumptions, including TSO, PSO, and RC11. In addition, TruSt is embarrassingly parallelizable: its different exploration options have no shared state, and can therefore be explored completely in parallel. Consequently, TruSt outperforms the state-of-the-art in terms of memory and/or time.

Industrial-Strength Controlled Concurrency Testing for $$\textsc {C}{} \texttt {\#} $$ Programs with $$\textsc {Coyote} $$

“…Exhaustive techniques are based on the notion of partial order reduction (POR) [24] that constructs equivalence classes of executions so that only one exploration per equivalence class is required [35]. Recently, this line of work has produced several tools, such as CDSChecker [47], GenMC [30], and Nidhugg [2], that have demonstrated value in verifying concurrency primitives (e.g., latches, mutex implementations) and concurrent data structures, especially when considering weak memory behaviors [1,28,29].…”

Abstractions for the local-time semantics of timed automata: a foundation for partial-order methods

“…Later the accent shifted to program verification, and in particular to stateless model-checking [21]. The subject has become very active since the work of Abdulla et al [1,2] introducing a notion of optimal partial order reduction (see [14,28,40] and references within). In this paper we take an abstract view of partial-order methods and do not focus on any concrete methods.…”

Depth-First Net Unfoldings and Equivalent Reduction

“…Exploring the path of a concurrent system [1][2][3][4] may lead to a state space explosion. Partial order semantics [2,[5][6][7][8][9][10][11] and prime event structure have proven to be efficacious techniques in alleviating state space explosions during traversal. The concurrency of the Petri net is a valuable tool for concurrent system modeling.…”

“…As has been widely acknowledged in the literature, the correctness of the searchi.e., the assurance that the search will always terminate with the correct result-is highly dependent on the strategy employed [6]. Several papers [6,7,12] have proposed breadthfirst strategies that have been shown to be correct.…”